It is sometimes desired to provide a capability to extend wireless networking capabilities from the terrestrial to the underwater domain, using through-water acoustic communications. To do this, a number of modem repeater nodes in a fixed network and associated equipment can make up an undersea communication grid. This provides an undersea network capable of providing connectivity between underwater fixed sensor grids, as well as between underwater networks and above water mobile platforms and command centers for various types of systems, platforms, missions, and sensor networks.
There can often be inherent difficulties in establishing underwater networks. The first difficulty can be transporting each network node to its desired underwater location. It may often more convenient to transport the nodes underwater. In this case, it can be further desired to maneuver the nodes to a precise location manually with a diver. If the nodes are negatively buoyant, this can result in a diver attempting to manually maneuver a node that might weigh over a hundred pounds, which is obviously an undesirable situation that should be avoided if at all possible.
Once nodes have been positioned according to the user's needs, it can be desired to anchor the nodes so that they remain in position with respect to other nodes for optimum communications, (such as data transfer, by way of non-limiting example) according to the prevailing undersea conditions (water temperature, existence of thermoclines, etc.). But underwater forces such as current can move the nodes to an undesired location without the knowledge of the network operator. This can cause decreased network performance, and in extreme cases, the movement of the nodes can make the network inoperable.
In view of the above, it is an object of the present invention to provide an underwater network with nodes that are neutrally buoyant during underwater transport. It is another object of the present invention to provide an underwater network with nodes that can be transported by a single diver, with or without the aid of an underwater transport system such as a Seal Delivery Vehicle (SDV). Another object of the present invention to provide an underwater network with nodes that have a low hydrodynamic drag to facilitate delivery underwater. Yet another object of the present invention is to provide an underwater network with nodes that allow for ballasting to create negative buoyancy for the node once it is desired to deploy the node to fix the node in position on the ocean or harbor floor. Still another object of the present invention is to provide an underwater network with nodes that provide anchoring and anti-roll effects that self-orient the nodes with respect to the sea/harbor bottom once deployed. More generally, another object of the present invention is to provide a method for delivery of a payload underwater that uses a neutrally buoyant housing, which can be flooded to deploy the payload according the needs of the user.